Viscoelastic behavior of silicone/clay nanocomposite coatings

Abstract

Rubber/clay nanocomposites (RCNs) have attracted an emerging interest from academia and industry alike due to their outstanding tunable properties. The present paper addresses the viscoelastic behavior of silicone/clay systems in order to get an understanding of physical interactions in the RCNs systems as well as making possible interpretation of the effect of nanoparticle shape and surface functionality on viscoelastic behavior of molten RCNs. Rheological behavior determination of silicone/clay composites provides insight into dependency of properties of resulting nanocomposite coatings on processing and preparation conditions. The effect of bare and (3-aminopropyl) triethoxysilane (APTES) functionalized platy and tubular clays on viscoelastic behavior of silicone rubber nanocomposites were investigated by rheometric mechanical spectrometer (RMS). The analysis was set to the strain and frequency sweep tests, where the linear viscoelastic zone of the uncured nanocomposites were determined by dynamic strain sweep and then frequency sweep to probe into the role of dispersion of nanoparticles in silicone matrix. Well-known Han, Cole-Cole and van Gurp-Palmen models were applied to peruse silicone/clay interaction and to find additional information on rheological properties of nanocomposites under the influence of the shape, surface chemistry and content of nanoparticles. The findings depicted the effective role of physical interactions on APTES-functionalized clay on appropriate dispersion of clays throughout silicone matrix. This effect was more obvious in the presence of platelet-like clays in view of improved intercalation and/or exfoliation.